Safety, Tolerability and Immune Response of IMVAMUNE (MVA-BN)Smallpox Vaccine in HIV Infected Patients

Inclusion Criteria: * Male subjects between 18 and 49 years of age or female subjects between 18 and 55 years of age who provided informed consent. * Women with negative pregnancy test. * Women of childbearing potential must use an acceptable method of contraception. * Cardiac enzymes within ULN. * White blood cells ≥ 2500/mm3 and \< 11,000/ mm3. * Absolute neutrophil count ≥ 1000/mm3. * Adequate renal function. * Adequate hepatic function. * Negative hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (anti-HBc). * Negative antibody test to hepatitis C virus (HCV). * Negative urine glucose by dipstick or urinalysis. * Normal 12-lead electrocardiogram. * Availability for follow-up during the study. Groups 1 and 3 (All vaccinia-naïve subjects) additionally: * No history of known or suspected previous smallpox vaccination. * No detectable vaccinia scar. * No military service prior to 1989 or after January 2003. Groups 2 and 4 (All previously vaccinated subjects) additionally: * History of at least one previous smallpox vaccination * Time since most current smallpox vaccination \> 10 years. Groups 1 and 2 (All HIV Infected subjects) additionally: * Documented HIV-1 infection * Plasma HIV-1 RNA level \< 400 copies/mL at screening. * CD4 cells ≥ 350/µL * Haemoglobin ≥ 9.0 g/dL. * Platelets ≥ 100,000/mm3. * AST (SGOT), ALT (SGPT) and alkaline phosphatase ≤ 3 x ULN Groups 3 and 4 (All Healthy subjects) additionally: * Negative ELISA for HIV. * Haemoglobin \>11 g/dL. * Platelets ≥ 140,000/mm3. * AST (SGOT), ALT (SGPT) and alkaline phosphatase without clinically significant findings Exclusion Criteria: * Pregnant or breast-feeding women. * Uncontrolled serious infection i.e. not responding to antimicrobial therapy. * History of any serious medical condition (other than HIV infection). * History of or active autoimmune disease. * Known or suspected impairment of immunologic function (other than HIV infection). * History of malignancy. * History or clinical manifestation of clinically significant and severe haematological, renal, hepatic, pulmonary, central nervous, cardiovascular or gastrointestinal disorders. * Clinically significant mental disorder not adequately controlled by medical treatment. * Any condition which might interfere with study objectives. * History of coronary heart disease, myocardial infarction, angina, congestive heart failure, cardiomyopathy, stroke or transient ischemic attack, uncontrolled high blood pressure, or any other heart condition under the care of a doctor. * History of an immediate family member with onset of ischemic heart disease before age 50. * Ten percent or greater risk of developing a myocardial infarction or coronary death within the next 10 years using the National Cholesterol Education Program's risk assessment tool. * History of chronic alcohol abuse and/or intravenous drug abuse. * History of allergic disease or reactions likely to be exacerbated by any component of the vaccine. * Known previous allergic reaction to immunoglobulins. * Known allergies to cidofovir or probenecid. * History of anaphylaxis or severe allergic reaction. * Acute disease (illness with or without a fever) at the time of enrollment. * Temperature \>100.4°F at the time of enrollment. * Subjects undergoing treatment for tuberculosis infection or disease. * Having received any vaccinations or planned vaccinations with a live vaccine within 30 days prior or after study vaccination. * Having received any vaccinations or planned vaccinations with a killed vaccine within 14 days prior or after study vaccination. * Chronic administration of immuno-suppressant or immune-modifying drugs. * Post organ transplant subjects whether or not receiving chronic immunosuppressive therapy. * Administration or planned administration of immunoglobulins and/or any blood products. * Use of any investigational or non-registered drug or vaccine.